Question

Assume that each atom in a copper wire contributes one free electron. Estimate the number of free electrons in a copper wire having a mass of 6.4 g (take the atomic . weight of copper to be 64 g/mol).

Answer 1

64 grams of copper have 1 mole 6.4 grams of copper have 0.1 mole
1 mole = No atoms 0.1 mole = (no × 0.1) atoms
= 6 × 10²³ × 0.1 atoms = 6 × 10²² atoms
1 atom contributes 1 electron 6 × 10²² atoms contributes 6 × 10²²  electrons.